This invention is directed to novel crystalline polyarylnitrile polymers and a process for their production.
A poly(arylether ketone) having the following formula: ##STR1## is well known in the prior art. It is a crystalline polymer having excellent mechanical and thermal properties. It is useful for coating wire and cable and can be molded into products such as electrical connectors of superior performance.
However, the poly(arylether ketone) is prepared by the following procedure: ##STR2## Thus, the preparation of the poly(arylether ketone) is not only difficult, but also requires the use of hydrofluoric acid as solvent and boron trifluoride as catalyst which are poisonous, detrimental to the environment and otherwise hazardous to work with.
Attempts have been made to develop other methods of synthesizing the poly(arylether ketone) without the use of hydrofluoric acid, or alternatively, to develop other polymers with properties comparable to those of this poly(arylether ketone).
U.S. Pat. No. 3,730,946 is directed to particular amorphous cyanoaryloxy polymers prepared from the reaction of a dinitrobenzene containing a cyano group, directly attached to the benzene nucleus, with an alkali metal salt of a divalent carbocyclic aromatic radical in the presence of a dipolar aprotic solvent. The cyanoaryloxy polymers of U.S. Pat. No. 3,730,946 are described as containing the following repeating unit: ##STR3##
These copolymers are not crystalline and do not have very high molecular weight. The polyarylnitrile of formula (I) below was never prepared in U.S. Pat. No. 3,730,946.
It has been found that the polyarylnitriles of this invention are crystalline high molecular weight polymers which have excellent mechanical and thermal properties and are comparable in performance to the poly(arylether ketone) described above. Further, these polyarylnitrile polymers are easily prepared as compared to the poly(arylether ketone).